I Found the solution myself.
How to recover any app you have only on your iPod (and not in iTunes) and you can not get in iTunes Store:
Preparation 1:
==> make sure in iTunes automatic sync for devices is switched off!!
- open preferences
- go to "devices"
- make sure the box is checked that...
different situation, same question:
I updated on my Mac in iTunes to iReal-b 4.5 (silly me!)
On my first-gen iPod I am still on iReal-b 4.4 - so its working there.
But how can I backup this running version to my mac?
thanks for any help.